1. Field of the Invention
The present invention relates to a translation machine for outputting a natural translated sentence, more particularly the translation machine which is capable of translating a sentence with an ambiguous parallel disposition of words and/or phrases into a correct sentence.
2. Description of the Related Art
The inventors of the present invention know a translation machine which is operated to enter a source language input from a keyboard into a translation module under a control of a main central processing unit (CPU). The translation module serves to translate the source language into a target language by using dictionaries and by following rules such as grammatical rules and tree-structure transforming rules stored in a memory.
In a translation operation, a syntactic of the source language is analyzed in the translation module as follows. The words composing one sentence contained in the read source language are stored in a buffer. Using the dictionary stored the memory, the translation module serves to derive a part speech of each word stored in the buffer. Then, proper grammatical rules are picked out of the memory for setting up the modifying relation among the parts of speech of the words. Based on the picked grammar rules, a structure analyzing tree is created for indicating how the words composing the sentence being modified. The syntactic analyzing tree of the source language is transformed into the syntactic analyzing tree of the target language, from which the translated sentence of the target language is created.
When the English sentence of "He played cards in the room, the yard, and the garage of his house." (the source language is herein assumed to be English) is input to the known translation module, the translation module provides no means for determining the parallel disposition of three phrases "the room", "the yard" and "the garage". According to the grammatical rules, therefore, the three phrases of "the room", "the yard" and "the garage of his house" are erroneously determined as parallel disposition. It results in the translation module serving to translate the English sentence into the target-language (herein, Japanese) translated sentence like:
(translated such that "his house" modifies only "the garage", though in actual "his house modifies all of "the room", "the yard" and "the garage".)
The known translation machine operates to build a syntactic analyzing tree for indicating how the words composing an input source-language sentence being modified by using the grammatical rules and to create the translated sentence of a target language on the basis of the syntactic analyzing tree of the source language. Hence, in case of inputting a sentence whose parallel disposition of the phrases and/or words is ambiguous or whose modifying structure of the words is ambiguous, it may be possible to obtain a plurality of grammatical rule groups from the memory, each grammatical rule group working for defining the modifying relation among the words composing the sentence. In such a case, it is possible to build all the possible syntactic analyzing trees, to obtain a plurality of translated sentences for those syntactic analyzing trees, and to output the obtained translated sentences in a predetermined sequence.
As such, if an operator determines the first output translated sentence of the target language is not proper, he or she gives an indication from the keyboard to the CPU so as to change the translated sentence alternatives in sequence and select the most appropriate one. This operation is very troublesome, because all the translated sentence alternatives are not displayed on a display device such as a cathode ray tube (CRT) simultaneously.